A continuously variable transmission performs power transmission by means of a V belt, for example, which is wrapped around a primary pulley into which an engine rotation is input and a secondary pulley on an output side which is joined to a vehicle wheel.
In a continuously variable transmission, the step count of a step motor is controlled to realize a target speed ratio, and as a result, the pressure of the primary pulley is controlled.
JP2004-100736A discloses a conventional device which, when controlling a line pressure serving as the source pressure of a primary pulley pressure and a secondary pulley pressure of a continuously variable transmission, takes a line pressure discrepancy caused by an error in the attachment of the step motor into account.